#include<stdio.h>
#include<math.h>
int main()
{
    int a,b,c;
    double area,perimeter,s;
    scanf("%d%d%lf",&a,&b,&s);
    if((a+b)>c&&(a+c)>b&&(b+c)>a)
    {
        s = (a+b+c)/2.0;
        area = sqrt(s*(s - a)*(s - b)*(s - c));
        perimeter = a+b+c;
        printf("area = %.2lf; perimeter = %.2lf;",area,perimeter);
    }
    else
    {
        printf("These sides do not correspond to a valid triangle");
    }
    return 0;
}
